Rotary pumps without shaft packing



Oct. 30, 1962 w. BUSCHHORN ETAL 3,060,861 ROTARY PUMPS WITHOUT SHAFT PACKING Filed June 15, 1959 FIG. I

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nited States atent 3,060,861 ROTARY PUMPS WITHOUT SHAFT PACKING Walther Buschhorn and Friedrich Stein, Pegnitz, Upper Franconia, Germany, assignors to Klein, Schanzlin & Becker Aktiengesellschaft, Frankenthal, Pfalz, Germany Filed June 15, 1959, Ser. No. 820,507 12 Claims. (Cl. 103-457) Rotary pumps without shaft packing are, in known manner, combined with the electric driving motor to form a complete aggregate, whereby the impeller of the rotary pump and the rotor of the electric driving motor are mounted on a common shaft supported at both ends. To prevent the insulation of the stator coils from being damaged by the liquid being pumped filling the motor compartment, a liner tube or casing is arranged in the gap between the rotor and stator and its ends are attached to the motor and pump housing respectively by a watertight connection. In the case of pumps of this type care must be taken that no foreign bodies, such as dirt or the like, entrained by the liquid being pumped, enter the gap between the rotor and the wall of the liner tube and there block the rotor or cause more serious damage.

This is avoided according to the invention by providing between the impeller and rotor a compartment of greater diameter than that of the rotor compartment and in which, thanks to the rotary movement imparted by the rotating rotor to the liquid being pumped, foreign bodies in the rotor compartment can collect.

A simple and advantageous construction of the collecting compartment is obtained by enlarging the liner tube or casing beyond the coil ends on the pump side. The collecting compartment is preferably limited on the pump side by a wall constructed as a cover forming at the same time the lateral boundary wall of the impeller from which it is arranged at such a distance that a minimum amount of friction is ensured on the impeller side without affecting the size of the collecting chamber. At the same time the passage of particles of dirt to the collecting compartment is restricted by the wall. Holes are provided near the outer diameter of the wall through which the motor and collecting compartments are completely filled with the liquid being pumped and good venting is ensured.

In another embodiment of the invention, using a liner casing for screening the stator from the liquid being pumped, this casing is centered on the pump housing by a seat or static bearing surface on its enlarged portion forming the radial boundary wall of the collecting compartment. The support for the rotor bearing is fixed in the bottom end of the liner casing. This support is preferably pressed tightly into the liner casing and made from a material the coeflicient of thermal expansion of which is greater than or equal to that of the liner casing material. This measure prevents in a reliable manner the bearing support from becoming loose in the liner casing in the event of fluctuations in temperature.

An embodiment of the invention is illustrated by way of example in the accompanying drawing, in which:

FIG. 1 shows in axial section a pump aggregate without shaft packing, in which the screening of the stator from the liquid being pumped is effected by a liner casing, and

FIG. 2 is a plan view of the support for the rotor bearing.

In FIG. 1 the common shaft designated by 1 carries the impeller 2 and the rotor 3. The shaft 1 is supported in bearings at its two ends 4 and 5. Stator 6 is screened from the liquid being pumped by a liner casing 7 fixed with a watertight connection on the pump housing 8. Between the impeller 2 and rotor 3 a collecting chamber 9 is provided, the diameter D of this compartment being greater than the diameter d of the rotor compartment 10 and located in front of the coil ends 11 of the stator on the pump side. This collecting compartment is formed by an enlargement 12 of the liner casing and limited on the pump side by a wall 13 constructed as a cover with vent holes 14 near its outer diameter and constituting at the same time the lateral boundary wall for the impeller. The distance e between this wall and the impeller is so chosen that friction on the wheel or impeller side is reduced to a minimum and the size of the collecting compartment is not affected. The enlargement 12 of the liner casing is provided on the outer side with a fitting area or static bearing surface 15 by which the liner casing is centered on the pump housing. A support 17 for the rotor bearing 18 is tightly pressed into the part 16 at the bottom end of the liner casing. Apertures 21 (FIG. 2) are provided between the hub 19 of the support carrying the bearing 18 and its outer boundary surface 20 and the hub is provided with spacer blocks 23 hearing against the bottom 22 of the liner casing to enable effective flushing of the bearing. Recesses 24 (FIG. 2) are provided for ventilation in the boundary surface 20 of the bearing support.

The collecting chamber 9 which has a diameter D greater than the diameter d of the rotor compartment 10 collects the foreign bodies, such as mud, sand and particles of scale from the pipe line which cannot be prevented from passing out of the liquid flowing through the pump into the rotor compartment. These particles are centrifuged outwardly of the chamber 9 and collect adjacent the apertures of vent holes 14. Since the vent holes are disposed adjacent the outer rim of the impeller 2, a suction occurs thereat which readily removes the foreign bodies within the area of the apertures. The collecting compartment is preferably located outside the coil ends, when viewed in the axial direction so as to prevent magnetizable particles, such as particles of scale composed of Fe O from collecting in the range of effective lines of force of the stator. The apertures 21 provided in the hub 19 provide an effective flushing of the rotor bearing and the recesses 24 provided in the boundary surface 20 of the bearing support provide ventilation of the space between the bottom of the liner casing and the bearing support.

We claim:

1. A rotary pump without shaft packing and forced oil circulation combined with an electric driving motor to form a single unit and including an impeller for conveying contaminated liquids, said motor including a rotor and a stator surrounding said rotor, a housing for said unit, a single shaft rot-atably supported at each end thereof, said impeller and said rotor being mounted on said shaft intermediate the ends thereof, liner means extending between said rotor and stator and surrounding said rotor to form an enclosed watertight rotor compartment, said liner means including a portion spaced radially outwardly of the remainder thereof to form an essentially cylindrical chamber between said rotor and said impeller having a diameter greater than the diameter of said rotor compartment, wall means delimiting said cylindrical chamber and forming a lateral limiting wall of said impeller, and means allowing passage of said liquids through said rotor compartment, said cylindrical chamber forming a collecting chamber for collecting and containing foreign bodies contained in said liquid passing through said rotor compartment.

2. A rotary pump as defined in claim 1, wherein said delimiting wall is so constructed and arranged that a minimum amount of friction is ensured on the side of the impeller and the size of the compartment is not affected.

3. A rotary pump without shaft packing and forced oil circulation combined with an electric driving motor to form a single unit and including an impeller for conveying contaminated liquids, said motor including a rotor and a stator surrounding said rotor, a housing for said unit, a single shaft rotatably supported at each end thereof, said impeller and said rotor being mounted on said shaft intermediate the ends thereof, liner means extending between said rotor and stator and surrounding said rotor to form an enclosed Water-tight rotor compartment, said liner means including a cylindrical space between said rotor and said impeller having a diameter greater than the diameter of said rotor compartment, said liner means being so constructed and arranged that said cylindrical space extends beyond the outer diameter of said stator when viewed in the axial direction, wall means delimiting said cylindrical space and forming a lateral limiting wall of said impeller, and means allowing passage of said liquids through said rotor compartment, said cylindrical space forming a collecting chamber for collecting and containing foreign bodies contained in said liquid passing through said rotor compartment.

4. A rotary pump without shaft packing and forced oil circulation combined with an electric driving motor to form a single unit and including an impeller for conveying contaminated liquids, said motor including a rotor and a stator surrounding said rotor, a housing for said unit, a single shaft rotatably supported at each end thereof, said impeller and said rotor being mounted on said shaft intermediate the ends thereof, liner means extending between said rotor and said stator surrounding said rotor to form an enclosed water-tight rotor compartment, said liner means including a cylindrical space between said rotor and said impeller having a diameter greater than the diameter of said rotor compartment, said liner means being formed by a liner casing and said cylindrical space being formed by an enlargement of said liner casing, said cylindrical space extending beyond the end of said stator on the pump side thereof, wall means delimiting said cylindrical space and forming a lateral limiting wall of said impeller, and means allowing passage of said liquids through said rotor compartment, said cylindrical space forming a collecting chamber for collecting and containing foreign bodies contained in said liquid passing through said rotor compartment.

5. A rotary pump as defined in claim 4, wherein said enlargement extends beyond the outer edge of said stator when viewed in the axial direction.

6. 'A rotary pump as defined in claim 4, wherein said means allowing passage of liquid includes vent holes in the outer diameter of said delimiting wall.

7. A rotary pump as defined in claim 6, wherein said enlargement of said liner casing includes a static bearing surface, and means supporting said bearing surface at said housing.

8. A rotary pump as defined in claim 7, wherein means supporting said shaft include bearings at each end thereof, and support means for the bearing adjacent said rotor, said support means being tightly fitted into the end of said liner casing adjacent said rotor.

9. A rotary pump as defined in claim 8, wherein said support means includes an element provided between said bearing adjacent the rotor and the wall of the liner casing and spacer blocks bearing against the end of said liner casing adjacent said rotor, said element including apertures therein to allow flushing of said rotor bearing by said fluid flowing through said rotor compartment.

10. A rotary pump as defined in claim 4, wherein said enlargement of said liner casing includes a static bearing surface, and means supporting said bearing surface at said housing.

11. A rotary pump without shaft packing and forced oil circulation combined with an electric driving motor to form a single unit and including an impeller for conveying contaminated liquids, said motor including a rotor and a stator surrounding said rotor, a housing for said unit, a single shaft rotatably supported at each end thereof, said impeller and said rotor being mounted on said shaft intermediate the ends thereof, liner means extending between said rotor and said stator and surrounding said rotor to form an enclosed water-tight rotor compartment, said liner means including a cylindrical space between said rotor and said impeller having a diameter greater than the diameter of said rotor compartment, wall means delimiting said cylindrical space and forming a lateral limiting wall of said impeller, and means allowing passage of said liquids through said rotor compartment including vent holes in the outer diameter of said delimiting wall, said cylindrical space forming a collecting chamber for collecting and containing foreign bodies contained in said liquid passing through said rotor compartment.

12. A rotary pump without shaft packing and forced oil circulation combined with an electric driving motor to form a single unit and including an impeller for conveying contaminated liquids, said motor including a rotor and a stator surrounding said rotor, a housing for said unit, a single shaft rotatably supported at each end there of, said impeller and said rotor being mounted on said shaft intermediate the ends thereof, liner means extending between said rotor and stator and surrounding said rotor to form an enclosed water-tight rotor compartment, said liner means including a portion spaced radially outwardly of the remainder thereof to form an essentially cylindrically-shaped chamber between said rotor and said impeller having a diameter greater than the diameter of said rotor compartment, wall means delimiting said cylindrical chamber and forming a lateral limiting wall of said impeller, and means allowing passage of said liquids through said rotor compartment including aperture means in said wall means adjacent the outer edge of said impeller, said cylindrical chamber forming a collecting chamber for collecting and containing foreign bodies contained in said liquid passing through said rotor compart merit.

References Cited in the file of this patent UNITED STATES PATENTS 2,669,187 Guyer Feb. 16, 1954 2,805,626 Pezzillo et al. Sept. 10, 1957 2,809,590 Brown Oct. 15, 1957 2,875,694 Carter Mar. 3, 1959 FOREIGN PATENTS 1,049,446 France Dec. 29, 1953 

